1. Field of the Invention
The present invention relates to an image processing apparatus and image processing method, and more particularly, to an image processing apparatus and the like, capable of favorably performing an image quality improvement with respect to a low quality up-convert material in which horizontal strips occur.
2. Description of the Related Art
Recently, with the start of digital broadcasting, image data of HD (High Definition) resolution are transmitted from the broadcasting station or the like. However, not all the image data transmitted from the broadcasting station or the like are the image data of HD resolution and may include image data of pseudo-HD resolution obtained by up-converting the image data of SD (Standard Definition) resolution used in the analogue broadcasting in the related art into HD resolution.
The image data of pseudo-HD resolution include material (hereinafter, referred to as “low quality up-convert material) prepared by up-converting the interlaced image data of SD resolution using in-field linear interpolation in the same interlaced image data. For example, there are 1080i image data obtained by up-converting image data of 480i or image data of 576i.
Further, interlaced image data of SD resolution before up-convert also include image data prepared by converting progressive image data (frame material) with 24 frames or 30 frames per second using a 2-3 pull down scheme or a 2-2 pull down scheme.
In the case of the low quality up-convert material described above, when converting the interlace scheme into the progressive scheme for image display using the field interpolation, there was a shortcoming that horizontal strips occurred at portions having luminance differences in the vertical direction. This is because there occurs a state in which pixel proximity and pixel value proximity are not matched between a certain field and its adjacent field in the vertical direction, when up-converting the interlaced image data of SD resolution using in-field linear interpolation in the same interlaced image data.
For example, Japanese Unexamined Patent Application Publication No. 2008-85993 describes that it is determined whether image data are up-convert material or not by detecting signals having a plurality of frequency bands and on the basis of signal amplitude of each frequency band. Further, for example, Japanese Unexamined Patent Application Publication No. 2004-289753 describes that it is determined whether image data are up-convert material or not by existence of the side panel of the image data having HD resolution.